Method and a device for gunniting converter linings

ABSTRACT

A flame dusted with a pulverized refractory is directed tangentially to a lining surface and imparted a rotary motion, in which ducts are provided in a device and intended for the feeding onto a converter lining of a pulverized refractory, fuel and oxygen issuing from a nozzle whose axis is perpendicular to that of the ducts in a plane at right angle to a nozzle axis are deflected from a longitudinal axis at a 15*-90* angle.

United States Patent [1 1 Chemeris et al.

[ METHOD AND A DEVICE FOR GUNNITING CONVERTER LININGS [76] lnventors:Oleg Nikolaevich Chemeris, bulvar mira l8, kv. 69; Evgeny VasilievichTretyakov, ulitsa Rozy ljuxemburg, 30, kv. 32; Viktor KirillovichDidkovsky, ulitsa Rozy ljuxemburg 30a, kv. 42; Vilen Davidovich Kanfer,ulitsa Tsusimskaua, 63, kv. 17, all of Donetsk; Nikolai KonstantinovichPaschenko, ulitsa Makara Mazaua, 74, kv. l, Zhdanov, Donetskoi oblasti;Izmail Grigorievich Zeltser, prospekt Nakhimova, 154, kv. 29, Zhdanov,Donetskoi Oblasti; Grigory Mikhailovich Ljukimson, prospekt Lenina, 45,kv, l0, Zhdanov, Donetskoi Oblasti; Alexandr Nikolaevich Bashkatov,pereulok Sadkovy, 70, kv. 72, Zhdanov, Donetskoi Oblasti; BorisNikolaevich Melnikov, ulitsa Sechenova, 68, kv. 27, Zhdanov, DonetskoiOblasti; Miron Yakovlevich Medzhibozhsky, perelok Nakhimova, 5, kv. 26,Zhdanov, Donetskoi Oblasti; Ilya Alexandrovich Goldberg, ulitsaShaumiana, 47, kv. 35; Izrail Abramovich Juzefovsky, ulitsa Reshetova,5, kv. 55, both of Leningrad; Rafail Davidovich Ratmansky, ulitsallicha, 52, kv. 53; Viktor Nikolaevich Irkha, both of Zhdanov, DonetskoiOblasti; Jury Nikolaevich Borisov, Hovokuznetsk Kemerovskoi Oblasti;Fedor Filippovich Kurochkin, Zhdanov, Donetskoi Oblasti, all of U.S.S.R.

[ 1 May 13, 1975 22 Filed: Aug. 31, 1973 21 Appl. No.: 393,406

Related US. Application Data [63] Continuation of Ser. No. 221,655, Jan.28, 1972,

abandoned.

[52] US. Cl. 239/422; 239/1323; 239/552; 239/336; 239/602 [51] Int. Cl.F23d 11/16 [58] Field of Search 239/336, 602, 552, 422, 239/423, 132.3 X

[5 6] References Cited UNlTED STATES PATENTS 805,689 11/1905 Ward et al.239/336 1,918,799 7/1933 Conley 239/336 3,185,512 5/1965 Kilgore 232/6023,478,963 11/1969 Winn, Jr. 239/336 X 3,730,763 5/1973 Schlottmann et a1239/336 3,782,631 l/l974 Brockly 239/336 Primary Examiner-Lloyd L. KingAttorney, Agent, or Firml-lolman & Stern 7 1 ABSTRACT A flame dustedwith a pulverized refractory is directed tangentially to a liningsurface and imparted a rotary motion, in which ducts are provided in adevice and intended for the feeding onto a converter lining of apulverized refractory, fuel and oxygen issuing from a nozzle whose axisis perpendicular to that of the ducts in a plane at right angle to anozzle axis are deflected from a longitudinal axis at a l590 angle.

1 Claim, 2 Drawing Figures METHOD AND A DEVICE FOR GUNNITING CONVERTERLININGS This is a divisional, of application Ser. No. 221,655, filedJan. 28, l972 now abandoned.

FIELD OF THE INVENTION The present invention relates to metallurgy andis intended for hot patching converter linings by gunniting or gunning.

BACKGROUND OF THE INVENTION At present the hot patching of the converterlinings is carried out by the application of the wet gunniting process,for instance, by pulp-spraying.

Low quality of the gunite produced by the above method and conditionedby the need to introduce low melting-point binders and plasticizingagents into a gunnite batch; abrupt and deep cooling down of the liningsurface, to be repaired, resulting in thermal spalling of refractorymaterials; the need for the continuous heating up of the placed guniteto produce ceramic bonds between the grains of a highly refractoryconsistuent of the gunite; inadequate sticking to tar concrete(tar-dolomite refractories) these and a series of other disadvantages donot enable the wet gunniting procedures to be effectively used for thehot patching of the converter lining.

Widely known is also a method of gunniting the converter lining with theaid of a fuel-oxygen torch shoot ing a pulverized refractory fed intoits flame.

With the flame gunniting method the above disadvantages are practicallycompletely avoided. As to the quality aspects of the gunite, it rankswith the best types of highly-refractory burned articles: up to 3%porosity is'provided and a structure featuring a large number of directbonds; the gunite produced becomes selfsupporting during the gunnitinginterval; no thermal shock is encountered and depositing to tar concreteis quite adequate.

However in gunniting with a uniflow flame (the flame directed at rightangle to a working surface of the lining, being gunnited) peculiar tothe flame gunniting process is low gunning efficiency of low yield(gunning efficiency is a weight ratio of a gunite built-up to the liningzone under repair to that of a refractory gunite constituent fed to arepair zone). In that case the gunning efficiency or yield is usuallyequal to -20 percent but not in excess of 40 percent.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a device for gunniting converter linings which substantiallyincreases efficiency of gunniting, enable the production of a slagandheat-resistant gunite containing basic refractories, tar concretes amongthem, avoid the loss of usable time in gunite burning and preclude thepossibility of thermal spalling of the refractory lining during repairs.

According to the specified and other objects the apparatus used in amethod of gunniting a converter lining with a flame dusted with apulverized refractory, conforming to this invention, in such that thesaid flame is directed tangentially to the lining surface, and imparteda rotary motion relative to a longitudinal axis of the converter.

To put the above method into effect a device has been developedcomprising pipes or ducts arranged concentrically relative to each otherand intended for feeding onto a converter lining a pulverizedrefractory, fuel and oxygen to be issued from a nozzle whose axis is atright angle to that of the pipe lines with the latter being deflected,conforming to the present invention, from the longitudinal axis at al5-90 angle in a plane perpendicular to the nozzle axis.

To make the nature of the present invention more fully apparentdescribed below is an exemplary embodiment of the proposed device to beconsidered with due reference to the accompanying drawings, in which:

DESCRIPTION OF THE DRAWINGS FIG. 1 shows a converter and a gunnitingdevice, conforming to this invention; and

FIG. 2 is a cross-sectional view of ducts of a converter gunnitingdevice.

DESCRIPTION OF A PREFERRED EMBODIMENT A device for the flame gunnitingof converter linings is a tuyere hereinafter referred to as lance 1,attached mechanically on manipulator 2 mounted on selfpropelled truck 3On the opposite side manipulator 2 is connected to header 4, whichencloses flexible metal pipes 5, 6 and 7 whose purpose is to supply tolance 1 respectively a mixture of a pulverized refractory with the fueland oxygen and to feed and drain water which serves for cooling lance 1.

Self-propelled truck 3 is designed for handling both manipulator 2 andlance 1 over a shop working floor and for imparting lance 1 areciprocating motion in the course of gunniting. The manipulator allowsfixing lance 1 in a preset position in the converter interior impartingit during the gunniting operation, if necessary, a rotary motion over ageneratrix of a cone, altering simultaneously its angle of inclinationrelative to its axis of rotation.

Lance 1 consists of nozzle 8 and four ducts 9 arranged concentricallyand intended for supplying nozzle 8 with the mixture of the pulverizedrefractory with fuel and oxygen and water.

The refractory powder-fuel mixture is fed along central duct 10 (FIG. 2)while the second duct 11 is employed for feeding the oxygen underpressure. The third and fourth ducts 12 and 13 serve to supply and drainhigh-pressure water.

Maximum diameter of the external lance duct is mm with the minimumdiameter amounting to 108 mm. An axis of lance nozzle 8 is directed atright angle to the ducts, the latter being deflected from a longitudinalaxis at an angle of l590 in a plane perpendicular to the nozzle axis.

For continuous gunniting, the axis of nozzle 8 shall be tangential inrelation to a cylindrical surface of the lining of converter 14 (in FIG.1 the working surface of the converter lining is shown by a dotand-dashline) with nozzle 8 disposed in the immediate vicinity of the liningsurface.

Construction of lance 1 with nozzle 8 perpendicular to the axis of ducts9 makes it possible to shoot the flows of the pulverized refractorymixed with the fuel and oxygen against the lining of the convertercylindrical part, i.e., against lining sections exposed to the mostintensive wear. However due to a taper of a converter mouth straightducts 9 make possible impractical location of nozzle 8 near the surfaceof the cylindrical portion of the lining in a zone adjacent to a buttjoint with the converter mouth or near the surface of the convertermouth lining. Deflection of ducts 9 in a plane perpendicular to thenozzle axis at an angle of l590 which is close to a taper of theconverter 14 mouth, tends to eliminate the above disadvantage inherentin lances with straight-line ducts. However duct deflection shall bereduced to a minimum, as an increase in an angle of bending of the ductsresults in a substantial growth in duct weight and hence the weight ofthe lance, as a whole; in addition the resistance encountered by therefractory powder-fuel mixture on its way 'to the lance is also liableto increase. With ducts 9 deflected at an angle more than 90 seriousdifficulties can arise in introducing the device into the converterinterior prior gunniting and in removing it when the process iscompleted. That is why maximum deflection of the ducts shall not exceed90.

At present the device and the method of the flame gunniting ofconverters is employed for hot patching tar concrete lining of l30-toncapacity oxygen converters. The working part of lance 1 is 7,500 mm longwith its external diameter being equal to 108 mm. Ducts 9 of lance l arebended in two planes at right angle to each other: at a 90 angle at thenozzle and at 20 when spaced at a distance of 3,000 mm from the nozzle.By using the above nozzle up to 200 kg/min of the mixture containing thepulverized refractory and the fuel and up to 60 cub.m./min. of oxygencan be supplied to the converter lining.

The device functions as follows.

Upon tapping both the metal and the slag at a temperature of a workingsurface of a converter lining ranging from l,350 to 1,500 C lance 1 isintroduced into converter 14 (FIG.. 1) so that an axis of a straightlineportion of lance l coincides with a longitudinal converter axis. In thatcase nozzle 8 of lance 1 is always tangential to the working surface ofconverter 14 lining. Depending on the nature of hot patching, nozzle 8is spaced at a different distance apart from working surface 15 of thelining: at a distance of up to 0.1 of the diameter of converter 14 incontinuous gunniting and up to 0.1 0.3 of a converter diameter ingunniting lining sections subjected to local wear.

For flame gunniting the converter linings depending on the nature ofrepairs and type of the refractory being deposited, use may be made ofdifferent refractory materials mixed with solid pulverized fuel. Thus inthe continuous gunniting of a tar concrete lining a finely divided (withgrain size less than 0.1 mm) mix is utilized consisting of twocomponents: powdered magne site 60-70 percent and pulverized coke 30 40percent.

To initiate the gunniting process, the supply of the pulverizedrefractory-fuel mixture and the oxygen supply are simultaneously turnedon. The fuel issuing from nozzle 8 mixes with the oxygen, ignites andburns out forming wild high-temperature flame 15. On account oftangential relative to the working surface of converter 14, outflow ofthe streams containing the mixture of the pulverized refractory with thefuel and the oxygen, flame 15 and flue gases are imparted a rotary inrelation to the longitudinal axis of converter 14 motion within thecylindrical cavity of converter 14 (the direction of rotation of flame15 is indicated with arrows in FIG. 1). In a cross-sectional view ofconverter 14, the path of rotating gases looks like a series ofconcentric closed circles. On hitting the lining, particles of thepulverized refractory move over its working surface and on being heatedto a plastifying termperature stick to it. Cross-hatched sections inFIG. 1 show gunite 16 in cross-section, built-up to the lining. Theparticles rebounded from the lining surface are entrained by a flow ofrotating gases, driven back to the lining under the action ofcentrifugal force arising on account of different densities ofhigh-temperature gases and, on establishing again a contact with theworking surface of the lining, stick to it in a more remote region.

With lacne l fixed stationary in the course of gunniting, the thicknessof a built-up being deposited varies with both the diameter and heightof converter 14. Maximum build-up is exhibited in the primary annularzone at the point the flame mates with the converter lining. As aminimum spacing between nozzle 8 and the working surface of the liningincreases, the building-up thickness tends also to increase in theprimary zone. However when the minimum distance between nozzle 8 and thelining working surface exceeds 0.3 of an internal diametrer of converter14, intensity of rotation of flame l5 dusted with the pulverizedrefractory decreases abruptly with the quality of combustiondeteriorating also. This results in a substantial carry away of thepulverized refractory and in a lower gunite quality. That is why ingunniting lining zones subjected to local wear nozzle 8 shall be locatedat a distance of not over than 0.3 of the converter internal diameterfrom the working surface of the lining. In continuous gunniting, nozzle8 is imparted, with the aid of manipulator 2, a rotary motion inrelation to a longitudinal axis of converter 14 and with the aid ofself-propelled truck 3 an intermitent reciprocating movement. Maximumgunite build-up is progressively displaced at that both along thediameter and the height of converter 14 which allows producing a uniformin thickness gunite throughout the worn converter lining.

The proposed invention ensures high technical and economicalcharacteristics, which have been proved by long-term trials of themethod of the invention both of experimental tigs and on aproduction-scale. In the course of mastering the proposed method anddevice for the flame gunniting of converter linings an increase inlining service life has been achieved: by heats in gunniting tarconcrete refractories and by 50 heats in gunniting magnesiterefractories in a constant lining layer. Specific consumption of thepulverized refractory-fuel mixture per 1 ton of steel melted during theoperating period of a gunnited converter was equal respectively to 0.8kg/ton and 1.6 kg/ton. Converter downtime per each gunniting operationis 25 min. with the consumption of the pulverized refractory-fuelmixture equalling 5 tons at the above interval.

Flame gunniting by the application of the above method makes it possibleto reliably and effectively smear lining zones subjected to localburnout at the end of a compaign and to preclude practically completelypremature shutdown of a unit for lining replacement. This will allowplanning, a month schedule of cold repairs in a converter shop dependingon maximum lining durability.

What is claimed is:

1. A device for deposition of refractory material on linings of asymmetric converter by the cyclone method comprising a concentricallyarranged ducting for conveying pulverized refractory material and fuelto a nozzle mounted at one end of said ducting which ducting 6 has asubstantially straight main portion for extending being disposed withits axis substantially perpendicular along the longitudinal max of theconverter and a furto that of Said further portion and to a plane commonther portion extending from the main portion at an angle ofsubstantially to 90 to the main portion, the nozzle communicating withsaid further portion and 5 to said main portion and said furtherportion.

1. A device for deposition of refractory material on linings of asymmetric converter by the cyclone method comprising a concentricallyarranged ducting fOr conveying pulverized refractory material and fuelto a nozzle mounted at one end of said ducting, which ducting has asubstantially straight main portion for extending along the longitudinalaxix of the converter and a further portion extending from the mainportion at an angle of substantially 15* to 90* to the main portion, thenozzle communicating with said further portion and being disposed withits axis substantially perpendicular to that of said further portion andto a plane common to said main portion and said further portion.